Abstract: The disclosed method includes the steps of positioning an ultrasonic transmitter (50, 52) on the exterior body portion (54) of the valve (14), oriented so that the transmitted ultrasonic wave intercepts the path (46) of the closure member (30) at least at one location, and positioning an ultrasonic receiver on the body portion oriented to detect reflected ultrasonic waves when the closure member passes through such location. The valve body (20) is filled with water and the closure member is caused to move along the path. The transmitter and receiver are operated to generate an output signal trace (64) commensurate with the magnitude of the ultrasonic wave reflected from the closure member at the targeted locations along the path.

Abstract: A control system for overpressure protection of the reactor coolant boundary (14) in a nuclear power plant, comprising a pressure relief line (18a) having a power operated relief valve (24a) controlled by a circuit responsive to the condition of the reactor coolant and a control logic. The circuit includes a mode selector switch (80) having a NORMAL position (82) for establishing a full power overpressure relief valve setpoint (62) and a LTOP position (84) for establishing a low temperature overpressure relief setpoint (58). The control system logic opens the relief valve (24a) when (a) the mode switch is in the NORMAL position and the coolant pressure exceeds the full power setpoint (62), or (b) when the mode switch is in the LTOP position, the coolant temperature is less than a preselected value (52) and the coolant pressure exceeds the LTOP setpoint (58).